Latest xforce showed archangel does indeed have greater durability throughout. Although it's strange that he takes the fire of genocide and sunfire pretty well but still gets sliced up by wolverine and sabretooth.
@Buckshot: Adamantium's still king and on that note how does Midnighter plan to tear through it?
When did AoA Sabretooth get adamantium claws? As for how Midnighter might theoretically bypass Archangel's durability if it's actually too tough for him to just punch through, he's got a few options. He could shove a bomb down Archangel's throat, he could remove one of Wolverine's claws and put it through Archangel's face, he could snap archangel's neck, he could possible choke him out, and going off how he was knocked for a little bit of a loop when he was shot in the head, it's very possible that he could still be knocked out.